Antibacterial agents: soluble salts and aqueous formulations of pyronins

ABSTRACT

The invention provides salts of formula Ia, Ib, Ic, or Id: wherein variables are as described in the specification, as well as compositions comprising a salt of formula Ia-Id, methods of making such salts, and methods of using such salts as, e.g., inhibitors of bacterial RNA polymerase and as antibacterial agents.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Provisional Application No.62/630,117, filed Feb. 13, 2018, which is hereby incorporated byreference in its entirety.

GOVERNMENT FUNDING

This invention was made with government support under AI109713 awardedby the National Institutes of Health. The government has certain rightsin the invention.

BACKGROUND OF THE INVENTION

Bacterial infectious diseases kill 100,000 persons each year in the USand 11 million persons each year worldwide, representing nearly a fifthof deaths each year worldwide (Heron et al., Final Data for 2006.National Vital Statistics Reports, Vol. 57 (Centers for Disease Controland Prevention, Atlanta Ga.) and World Health Organization (2008) TheGlobal Burden of Disease: 2004 Update (World Health Organization,Geneva)). In the US, hospital-acquired bacterial infections strike 2million persons each year, resulting in 90,000 deaths and an estimated$30 billion in medical costs (Klevins et al., (2007) Estimating healthcare-associated infections and deaths in U.S. hospitals. Public HealthReports, 122, 160-166; Scott, R. (2009) The direct medical costs ofhealthcare-associated infections in U.S. hospitals and benefits ofprevention (Centers for Disease Control and Prevention, Atlanta Ga.)).Worldwide, the bacterial infectious disease tuberculosis kills nearly 2million persons each year. One third of the world's population currentlyis infected with tuberculosis, and the World Health Organizationprojects that there will be nearly 1 billion new infections by 2020, 200million of which will result in serious illness, and 35 million of whichwill result in death. Bacterial infectious diseases also are potentialinstruments of biowarfare and bioterrorism.

For six decades, antibiotics have been a bulwark against bacterialinfectious diseases. This bulwark is failing due to the appearance ofresistant bacterial strains. For all major bacterial pathogens, strainsresistant to at least one current antibiotic have arisen. For severalbacterial pathogens, including tuberculosis, strains resistant to allcurrent antibiotics have arisen.

Bacterial RNA polymerase (RNAP) is a proven target for antibacterialtherapy (Darst, S. (2004) Trends Biochem. Sci. 29, 159-162; Chopra, I.(2007) Curr. Opin. Investig. Drugs 8, 600-607; Villain-Guillot, P.,Bastide, L., Gualtieri, M. & Leonetti, J. (2007) Drug Discov. Today 12,200-208; Ho, M., Hudson, B., Das, K., Arnold, E., Ebright, R. (2009)Curr. Opin. Struct. Biol. 19, 715-723; and Srivastava et al. (2011)Curr. Opin. Microbiol. 14, 532-543). The suitability of bacterial RNAPas a target for antibacterial therapy follows from the fact thatbacterial RNAP is an essential enzyme (permitting efficacy), the factthat bacterial RNAP subunit sequences are highly conserved (permittingbroad-spectrum activity), and the fact that bacterial RNAP-subunitsequences are highly conserved in human RNAP I, RNAP II, and RNAP III(permitting therapeutic selectivity).

The rifamycin antibacterial agents function by binding to and inhibitingbacterial RNAP (Darst, S. (2004) Trends Biochem. Sci. 29, 159-162;Chopra, I. (2007) Curr. Opin. Investig. Drugs 8, 600-607;Villain-Guillot, P., Bastide, L., Gualtieri, M. & Leonetti, J. (2007)Drug Discov. Today 12, 200-208; and Ho, M., Hudson, B., Das, K., Arnold,E., Ebright, R. (2009) Curr. Opin. Struct. Biol. 19, 715-723). Therifamycins bind to a site on bacterial RNAP adjacent to the RNAP activecenter and prevent extension of RNA chains beyond a length of 2-3 nt.The rifamycins are in current clinical use in treatment of bothGram-positive and Gram-negative bacterial infections. The rifamycins areof particular importance in treatment of tuberculosis; the rifamycinsare first-line anti-tuberculosis agents and are among the fewantituberculosis agents able to kill non-replicating tuberculosisbacteria.

The clinical utility of the rifamycin antibacterial agents is threatenedby the existence of bacterial strains resistant to rifamycins (Darst, S.(2004) Trends Biochem. Sci. 29, 159-162; Chopra, I. (2007) Curr. Opin.Investig. Drugs 8, 600-607; Villain-Guillot, P., Bastide, L., Gualtieri,M. & Leonetti, J. (2007) Drug Discov. Today 12, 200-208; and Ho, M.,Hudson, B., Das, K., Arnold, E., Ebright, R. (2009) Curr. Opin. Struct.Biol. 19, 715-723). Resistance to rifamycins typically involvessubstitution of residues in or immediately adjacent to the rifamycinbinding site on bacterial RNAP—i.e., substitutions that directlydecrease binding of rifamycins.

In view of the public-health threat posed by rifamycin-resistant andmultidrug-resistant bacterial infections, there is an urgent need fornew antibacterial agents that (i) inhibit bacterial RNAP (and thus havethe same biochemical effects as rifamycins), but that (ii) inhibitbacterial RNAP through binding sites that do not overlap the rifamycinbinding site (and thus do not share cross-resistance with rifamycins.

A new drug target—the “switch region”—within the structure of bacterialRNAP has been identified (WO2007/094799; Mukhopadhyay, J. et al. (2008)Cell. 135, 295-307; see also Belogurov, G. et al. (2009) Nature. 45,332-335; Ho et al. (2009) Curr. Opin. Struct. Biol. 19, 715-723;Srivastava et al. (2011) Curr. Opin. Microbiol. 14, 532-543). The switchregion is a structural element that mediates conformational changesrequired for RNAP to bind and retain the DNA template in transcription.The switch region is located at the base of the RNAP active-center cleftand serves as the hinge that mediates opening of the active-center cleftto permit DNA binding and that mediates closing of the active-centercleft to permit DNA retention. The switch region can serve as a bindingsite for compounds that inhibit bacterial gene expression and killbacteria. Since the switch region is highly conserved in bacterialspecies, compounds that bind to the switch region are active against abroad spectrum of bacterial species. Since the switch region does notoverlap the rifamycin binding site, compounds that bind to the switchregion are not cross-resistant with rifamycins.

It has been shown that the α-pyrone antibiotic myxopyronin (Myx)functions through interactions with the bacterial RNAP switch region(WO2007/094799; Mukhopadhyay, J. et al. (2008) Cell. 135, 295-307; seealso Belogurov, G. et al. (2009) Nature. 45, 332-335; Ho et al. (2009)Curr. Opin. Struct. Biol. 19, 715-723; Srivastava et al. (2011) Curr.Opin. Microbiol. 14, 532-543). Myx binds to the RNAP switch region,traps the RNAP switch region in a single conformational state, andinterferes with formation of a catalytically competent transcriptioninitiation complex. Amino acid substitutions within RNAP that conferresistance to Myx occur only within the RNAP switch region. There is nooverlap between amino acid substitutions that confer resistance to Myxand amino acid substitutions that confer resistance to rifamycins and,accordingly, there is no cross-resistance between Myx and rifamycins.

A crystal structure of a non-pathogenic bacterial RNAP, Thermusthermophilus RNAP, in complex with Myx has been determined, and homologymodels of pathogenic bacterial RNAP, including Mycobacteriumtuberculosis RNAP and Staphylococcus aureus RNAP, in complex with Myxhave been constructed (WO2007/094799; Mukhopadhyay, J. et al. (2008)Cell. 135, 295-307; see also Belogurov, G. et al. (2009) Nature. 45,332-335; Ho et al. (2009) Curr. Opin. Struct. Biol. 19, 715-723;Srivastava et al. (2011) Curr. Opin. Microbiol. 14, 532-543). Thecrystal structure and homology models define interactions between RNAPand Myx and can be used to understand the roles of the “west” and “east”Myx sidechains as well as the Myx α-pyrone core.

U.S. Pat. Nos. 9,133,155, 9,187,446, 9,315,495 and 9,592,221 relate topyronin compounds that are reported to possess antibacterial activity.There is a need for pyronin antibacterial compounds with improvedsolubility.

SUMMARY OF THE INVENTION

The invention provides methods of preparing salts containing2-oxo-3,4-dihydro-2H-pyran-4-olate derivatives of pyronins, methods offormulating salts containing 3-acyl-2-oxo-3,4-dihydro-2H-pyran-4-olatederivatives of pyronins, and formulations of salts containing3-acyl-2-oxo-3,4-dihydro-2H-pyran-4-olate derivatives of pyronins. Thenew methods and new formulations are anticipated to have applications incontrol of bacterial gene expression, control of bacterial growth,antibacterial prophylaxis, antibacterial therapy, and drug discovery.

Applicant has discovered that salts containing2-oxo-3,4-dihydro-2H-pyran-4-olate derivatives of pyronins can beprepared readily, are stable, and are surprisingly highly soluble inco-solvent-free, surfactant-free, near-neutral-pH aqueous vehicles—morethan an order of magnitude more soluble than the corresponding freeacids.

Methods and formulations of this invention are suitable for single-dayor multi-day intravenous dosing in mammals, including humans.

Methods and formulations of this invention are suitable for single-dayor multi-day oral dosing in mammals, including humans.

An object of the invention is to provide antibacterial salts thatpossess improved aqueous solubility. Improved aqueous solubility allowsfor one or more of the following: formulation in co-solvent-free,surfactant-free aqueous vehicles, preparation of formulations suitablefor single-day or multi-day intravenous administration at effectivedoses, and preparation of formulations suitable for single-day ormulti-day oral administration at effective doses. Applicant hasdiscovered that the salts of formulae Ia, Ib, Ic, and Id describedherein exhibit markedly improved aqueous solubility.

The salts of the invention have utility as inhibitors of bacterial RNAP.

The salts of the invention also have utility as inhibitors of bacterialgrowth.

A particular object of this invention is to provide salts andpharmaceutical compositions that have utility in the treatment ofbacterial infection in a mammal.

Accordingly, in one embodiment the invention provides a salt of formulaIa, Ib, Ic, or Id:

wherein:

W is sulfur, oxygen, or nitrogen;

X, Y, and Z are individually carbon, sulfur, oxygen, or nitrogen,wherein at least two of

X, Y, and Z are carbon;

one of R¹ and R² is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, alkoxy, aryloxy,heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl,or C₁-C₁₀ alkoxy, is optionally substituted by at least one of halogen,hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, and wherein anyaryloxy or heteroaryloxy is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, or heteroaryl,wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroaryl isoptionally substituted by at least one of halogen, hydroxy, C₁-C₅ alkyl,or C₁-C₅ alkoxy; or one of R¹ and R² is a 5-6-membered saturated,partially unsaturated, or aromatic heterocycle that is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy; and the other of R¹ and R² is absent or isone of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy,wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy;

R³ is absent, or is one of H, C₁-C₂ alkyl, or halogen-substituted C₁-C₂alkyl;

R⁴ is absent, or is one of H, halogen, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl;

V′, W′, X′, Y′, and Z′ are individually carbon or nitrogen; wherein atleast three of V′, W′,

X′, Y′, and Z′ are carbon;

one of R′ and R^(2′) is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, orheteroaryl, wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroarylis optionally substituted by at least one of halogen, hydroxy, C₁-C₅alkyl, or C₁-C₅ alkoxy;

or one of R^(1′) and R^(2′) is a 5-6-membered saturated, partiallyunsaturated, or aromatic heterocycle that is optionally substituted byat least one of halogen, hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, orC₁-C₁₀ alkoxy; and the other of R^(1′) and R^(2′) is absent or is one ofH, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy, wherein anyC₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy is optionally substitutedby at least one of halogen, hydroxy, or C₁-C₅ alkoxy;

R^(3′), R^(4′), and R^(5′) are each independently absent, H, halogen,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl;

W″ is sulfur, oxygen, or nitrogen;

U″, V″, X″, Y″, and Z″ are individually carbon, sulfur, oxygen, ornitrogen, wherein at least three of U″, V″, X″, Y″, and Z″ are carbon;

one of R^(1″) and R^(2″) is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, orheteroaryl, wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroarylis optionally substituted by at least one of halogen, hydroxy, C₁-C₅alkyl, or C₁-C₅ alkoxy; or one of R^(1″) and R^(2″) is a 5-6-memberedsaturated, partially unsaturated, or aromatic heterocycle that isoptionally substituted by at least one of halogen, hydroxy, C₁-C₁₀alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the other of R^(1″) andR^(2″) is absent or is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl,or C₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀alkoxy is optionally substituted by at least one of halogen, hydroxy, orC₁-C₅ alkoxy;

R^(3″) is absent or is one of H, C₁-C₂ alkyl, or halogen-substitutedC₁-C₂ alkyl;

R^(4″), R^(5″), and R^(6″) are each independently absent, H, halogen,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl;

R⁶ is H, halogen, or methyl that is optionally substituted by halogen;

G is one of —CH═CH—NHC(O)—R⁷, —CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷,—CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷, or —CH₂NHNHC(S)—R⁷,

R⁷ is one of C₁-C₆ alkyl, —O(C₁-C₆ alkyl), —S(C₁-C₆ alkyl), or —N(R⁸)₂;

each R⁸ is independently one of hydrogen or —C₁-C₆ alkyl;

R⁹ is C₁-C₁₀ alkyl or C₂-C₁₀ alkenyl, wherein any C₁-C₁₀ alkyl or C₂-C₁₀alkenyl is optionally substituted by at least one of halogen, hydroxy,alkoxy, or NR^(a)R^(b);

one of R¹² and R¹³ is hydrogen or C₁-C₄ straight alkyl, and the other ofR¹² and R¹³ is C₁-C₁₀ straight or branched alkyl, C₂-C₁₂ straight orbranched hydroxyalkyl, C₂-C₁₂ straight or branched alkenyl, C₂-C₁₂straight or branched hydroxyalkenyl, phenyl, C₇-C₁₂ aralkyl, C₇-C₁₂(aryl)hydroxyalkyl, C₆-C₁₂ heteroaralkyl, C₆-C₁₂(heteroaryl)hydroxyalkyl, or R¹² and R¹³ are taken together with theirintervening atom to form a 4-6 membered ring having 0-1 ring heteroatomsselected from nitrogen, oxygen or sulfur, said ring optionallysubstituted by one or two C₁-C₆ alkyl, C₂-C₆ alkenyl or hydroxyalkylgroups, wherein an alkyl, aryl or heteroaryl moiety of R¹² and R¹³optionally is substituted with 1-3 groups independently selected fromhalo, —C₁-C₆ hydroxyalkyl, —C₁-C₄ alkoxy, —C₁-C₄ trifluoroalkoxy, —CN,—C₁-C₄ alkoxycarbonyl, —C₁-C₄ alkylcarbonyl, —S(C₁-C₄ alkyl), and—SO₂(C₁-C₄ alkyl);

each R^(a) is independently C₁-C₁₀ alkyl that is optionally substitutedby at least one of halogen, hydroxy, or C₁-C₅ alkoxy;

each R^(b) is independently H or C₁-C₁₀ alkyl that is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy; and

M⁺ is a pharmaceutically acceptable cation. The invention also providesa salt of formula Ia, Ib, Ic, or Id for use in medical treatment.

The invention also provides a salt of formula Ia, Ib, Ic, or Id for usein the prophylaxis or treatment of a bacterial infection.

The invention also provides a composition comprising a salt of formulaIa, Ib, Ic, or Id and a pharmaceutically acceptable carrier. In oneembodiment the composition is sutable for intravenous administration. Inone embodiment the pharmaceutically acceptable carrier is water. In oneembodiment the composition is substantially free of organic co-solvents.In one embodiment the composition is substantially free of surfactants.The invention also provides the use of a salt of the invention as aninhibitor of a bacterial RNA polymerase.

The invention also provides the use of a salt of the invention as anantibacterial agent.

The invention also provides the use of a salt of the invention as adisinfectant, a sterilant, an antispoilant, an antiseptic, or anantiinfective.

The invention also provides the use of a salt of formula Ia, Ib, Ic, orId for the preparation of a medicament for prophylaxis or treatment of abacterial infection in a mammal.

The invention also provides a method of inhibiting a bacterial RNApolymerase, comprising contacting a bacterial RNA polymerase with a saltof the invention.

The invention also provides a method of treating a bacterial infectionin a mammal, comprising administering to the mammal a therapeuticallyeffective amount of a salt of formula Ia, Ib, Ic, or Id.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The following definitions are used, unless otherwise indicated.

The term “halo” means fluoro, chloro, bromo, or iodo.

The term “alkyl” used alone or as part of a larger moiety, includes bothstraight and branched chains. For example, C₁-C₁₀ alkyl includes bothstraight and branched chained alkyl groups having from one to ten carbonatoms. The term alkyl also includes cycloalkyl groups (e.g. cyclopropyl,cyclobutyl, cyclopently, cyclohexyl, cycloheptyl, and cyclooctyl), aswell as (cycloalkyl)alkyl groups (e.g. 3-cyclohexylpropyl,cyclopentylmethyl, 2-cyclohexylethyl, and 2-cyclopropylethyl).

The term “alkenyl” used alone or as part of a larger moiety, includes analkyl that has one or more double bonds. For example, C₂-C₁₀ alkenylincludes both straight and branched chained groups having from two toten carbon atoms and one or more (e.g. 1, 2, or 3) double bonds, as wellas (cycloalkyl)alkyl groups having one or more double bonds in thecycloalkyl portion or in the alkyl portion of the (cycloalkyl)alkyl.

The term “alkoxy” used alone or as part of a larger moiety is a groupalkyl-O—, wherein alkyl has any of the values defined herein.

The term “aryl” denotes a phenyl radical or an ortho-fused bicycliccarbocyclic radical having about nine to ten ring atoms in which atleast one ring is aromatic. For example, aryl can be phenyl, indenyl, ornaphthyl.

The term “heteroaryl” encompasses a radical of a monocyclic aromaticring containing five or six ring atoms consisting of carbon and one tofour heteroatoms each selected from the group consisting of non-peroxideoxygen, sulfur, and N(X) wherein X is absent or is H, O, (C₁-C₄)alkyl,phenyl or benzyl, as well as a radical of an ortho-fused bicyclicheterocycle of about eight to ten ring atoms comprising one to fourheteroatoms each selected from the group consisting of non-peroxideoxygen, sulfur, and N(X). For example heteroaryl can be furyl,imidazolyl, triazolyl, triazinyl, oxazoyl, isoxazoyl, thiazolyl,isothiazoyl, pyrazolyl, pyrrolyl, pyrazinyl, tetrazolyl, pyridyl, (orits N-oxide), thienyl, pyrimidinyl (or its N-oxide), indolyl,isoquinolyl (or its N-oxide) or quinolyl (or its N-oxide).

The term “heterocycle” or “heterocyclyl” ring as used herein refers to aring that has at least one atom other than carbon in the ring, whereinthe atom is selected from the group consisting of oxygen, nitrogen andsulfur. The ring can be saturated, partially unsaturated, or aromatic.The term includes single (e.g., monocyclic) saturated, partiallyunsaturated, and aromatic rings (e.g., 3, 4, 5, 6 or 7-membered rings)from about 1 to 6 carbon atoms and from about 1 to 4 heteroatomsselected from the group consisting of oxygen, nitrogen and sulfur in thering. In one embodiment the term includes 5-6 membered saturated,partially unsaturated, and aromatic heterocycles that include 1-5 carbonatoms and 1-4 heteroatoms.

A bond designated

herein represents a double bond that can optionally be cis, trans, or amixture thereof.

A combination of substituents or variables is permissible only if such acombination results in a stable or chemically feasible salt. The term“stable salts,” as used herein, refers to salts which possess stabilitysufficient to allow for their manufacture and which maintain theintegrity of the salt for a sufficient period of time to be useful forthe purposes detailed herein (e.g., formulation into therapeuticproducts, intermediates for use in production of therapeutic salts,isolatable or storable intermediate salts, treating a disease orcondition responsive to therapeutic agents.

Unless otherwise stated, structures depicted herein are also meant toinclude all stereochemical forms of the structure (i.e., the R and Sconfigurations for each asymmetric center). Therefore, singlestereochemical isomers, as well as enantiomeric and diastereomericmixtures, of the present salts are within the scope of the invention.Similarly, E- and Z-isomers, or mixtures thereof, of olefins within thestructures also are within the scope of the invention.

Unless otherwise stated, structures depicted herein also are meant toinclude salts that include one or more isotopically enriched atoms. Forexample, salts having the present structures except for the replacementof a hydrogen atom by a deuterium or tritium, or the replacement of acarbon by a ¹³C- or ¹⁴C-enriched carbon, are within the scope of thisinvention.

Salts of this invention may exist in tautomeric forms, such as keto-enoltautomers. The depiction of a single tautomer is understood to representthe salt in all of its tautomeric forms.

The term “pharmaceutically acceptable,” as used herein, refers to acomponent that is, within the scope of sound medical judgment, suitablefor use in contact with the tissues of humans and other mammals withoutundue toxicity, irritation, allergic response and the like, and arecommensurate with a reasonable benefit/risk ratio.

The term “pharmaceutically acceptable cation” includes sodium,potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper,manganese, aluminum and the like. Particularly acceptable cations arethe monovalent catins, including sodium, potassium, lithium, andammonium, and the like. The term pharmaceutically acceptable cation”also includes cations formed by protonation or alkylation of apharmaceutically acceptable organic nontoxic bases such as primary,secondary, and tertiary amines, substituted amines including naturallyoccurring substituted amines, cyclic amines and basic ion exchangeresins. For example, the term “pharmaceutically acceptable cation”includes cations formed from unsubstituted or hydroxyl-substitutedmono-, di-, or tri-alkylamines, dicyclohexylamine; tributyl amine;pyridine; N-methyl, N-ethylamine; diethylamine; triethylamine; mono-,bis-, or tris-(2-OH—(C₁-C₆)-alkylamine), such asN,N-dimethyl-N-(2-hydroxyethyl)amine or tri-(2-hydroxyethyl)amine;N-methyl-D-glucamine; morpholine; thiomorpholine; piperidine;pyrrolidine; and amino acids such as arginine, lysine, and the like.

Antibacterial Agents

The invention provides new compositions of matter that highly potentlyinhibit bacterial RNA polymerase and inhibit bacterial growth. Certainembodiments of the invention also provide methods for preparation of asalt according to general structural formula (Ia), (Ib), (Ic), or (Id).

Certain embodiments of the invention also provide an assay forinhibition of a RNA polymerase comprising contacting a bacterial RNApolymerase with a salt according to general structural formula (Ia),(Ib), (Ic), or (Id).

Certain embodiments of the invention also provide an assay forantibacterial activity comprising contacting a bacterial RNA polymerasewith a salt according to general structural formula (Ia), (Ib), (Ic), or(Id).

Certain embodiments of the invention also provide the use of a saltaccording to general structural formula (Ia), (Ib), (Ic), or (Id) as aninhibitor of a bacterial RNA polymerase.

Certain embodiments of the invention also provide the use of a saltaccording to general structural formula (Ia), (Ib), (Ic), or (Id) as anantibacterial agent.

Certain embodiments of the invention also provide the use of a saltaccording to general structural formula (Ia), (Ib), (Ic), or (Id) as oneof a disinfectant, a sterilant, an antispoilant, an antiseptic, or anantiinfective.

In a certain embodiment for a salt of formula Ia, Ib, Ic, or Id:

W is sulfur, oxygen, or nitrogen;

X, Y, and Z are individually carbon, sulfur, oxygen, or nitrogen,wherein at least two of X, Y, and Z are carbon;

one of R¹ and R² is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅ alkoxy, wherein anyC₁-C₅ alkyl and C₁-C₅ alkoxy is optionally substituted by at least oneof halogen, hydroxy, or C₁-C₅ alkoxy; or one of R¹ and R² is a5-6-membered saturated, partially unsaturated, or aromatic heterocyclethat is optionally substituted by at least one of halogen, hydroxy,C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the other of R¹ andR² is absent or is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, orC₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀alkoxy is optionally substituted by at least one of halogen, hydroxy, orC₁-C₅ alkoxy;

R³ is absent, or is one of H, C₁-C₂ alkyl, or halogen-substituted C₁-C₂alkyl;

R⁴ is absent, or is one of H, halogen, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl;

V′, W′, X′, Y′, and Z′ are individually carbon or nitrogen; wherein atleast three of V′, W′, X′, Y′, and Z′ are carbon;

one of R′ and R^(2′) is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅ alkoxy, wherein anyC₁-C₅ alkyl and C₁-C₅ alkoxy is optionally substituted by at least oneof halogen, hydroxy, or C₁-C₅ alkoxy; or one of R^(1′) and R^(2′) is a5-6-membered saturated, partially unsaturated, or aromatic heterocyclethat is optionally substituted by at least one of halogen, hydroxy,C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the other of R″ andR^(2′) is absent or is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl,or C₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀alkoxy is optionally substituted by at least one of halogen, hydroxy, orC₁-C₅ alkoxy;

R^(3′), R^(4′), and R^(5′) are each independently absent, H, halogen,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl;

W″ is sulfur, oxygen, or nitrogen;

U″, V″, X″, Y″, and Z″ are individually carbon, sulfur, oxygen, ornitrogen, wherein at least three of U″, V″, X″, Y″, and Z″ are carbon;

one of R^(1″) and R^(2″) is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅ alkoxy, wherein anyC₁-C₅ alkyl and C₁-C₅ alkoxy is optionally substituted by at least oneof halogen, hydroxy, or C₁-C₅ alkoxy; or one of R^(1″) and R^(2″) is a5-6-membered saturated, partially unsaturated, or aromatic heterocyclethat is optionally substituted by at least one of halogen, hydroxy,C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the other of R^(1″)and R^(2″) is absent or is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, orC₁-C₁₀ alkoxy is optionally substituted by at least one of halogen,hydroxy, or C₁-C₅ alkoxy;

R^(3″) is absent or is one of H, C₁-C₂ alkyl, or halogen-substitutedC₁-C₂ alkyl; R^(4″), R^(5″), and R^(6″) are each independently absent,H, halogen, C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl;

R⁶ is H, halogen, or methyl that is optionally substituted by halogen;

G is one of —CH═CH—NHC(O)—R⁷, —CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷,—CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷, or —CH₂NHNHC(S)—R⁷,

R⁷ is one of C₁-C₆ alkyl, —O(C₁-C₆ alkyl), —S(C₁-C₆ alkyl), or —N(R⁸)₂;

each R⁸ is independently one of hydrogen or —C₁-C₆ alkyl;

R⁹ is C₁-C₁₀ alkyl or C₂-C₁₀ alkenyl, wherein any C₁-C₁₀ alkyl or C₂-C₁₀alkenyl is optionally substituted by at least one of halogen, hydroxy,alkoxy, or NR^(a)R^(b);

one of R¹² and R¹³ is hydrogen or C₁-C₄ straight alkyl, and the other ofR¹² and R¹³ is C₁-C₁₀ straight or branched alkyl, C₂-C₁₂ straight orbranched hydroxyalkyl, C₂-C₁₂ straight or branched alkenyl, C₂-C₁₂straight or branched hydroxyalkenyl, phenyl, C₇-C₁₂ aralkyl, C₇-C₁₂(aryl)hydroxyalkyl, C₆-C₁₂ heteroaralkyl, C₆-C₁₂(heteroaryl)hydroxyalkyl, or R¹² and R¹³ are taken together with theirintervening atom to form a 4-6 membered ring having 0-1 ring heteroatomsselected from nitrogen, oxygen or sulfur, said ring optionallysubstituted by one or two C₁-C₆ alkyl, C₂-C₆ alkenyl or hydroxyalkylgroups, wherein an alkyl, aryl or heteroaryl moiety of R¹² and R¹³optionally is substituted with 1-3 groups independently selected fromhalo, —C₁-C₆ hydroxyalkyl, —C₁-C₄ alkoxy, —C₁-C₄ trifluoroalkoxy, —CN,—C₁-C₄ alkoxycarbonyl, —C₁-C₄ alkylcarbonyl, —S(C₁-C₄ alkyl), and—SO₂(C₁-C₄ alkyl);

each R^(a) is independently C₁-C₁₀ alkyl that is optionally substitutedby at least one of halogen, hydroxy, or C₁-C₅ alkoxy;

each R^(b) is independently H or C₁-C₁₀ alkyl that is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy; and

M⁺ is a pharmaceutically acceptable cation.

In a certain embodiment the salt of formula Ia is a salt of Ia′ and thesalt of formula Id is a salt of formula Id′

wherein:

W is sulfur, oxygen, or nitrogen;

X, Y, and Z are individually carbon, or nitrogen, wherein at least twoof X, Y, and Z are carbon;

one of R¹ and R² is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy,aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, andwherein any aryloxy or heteroaryloxy is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, orheteroaryl, wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroarylis optionally substituted by at least one of halogen, hydroxy, C₁-C₅alkyl, or C₁-C₅ alkoxy; or one of R¹ and R² is a 5-6-membered saturated,partially unsaturated, or aromatic heterocycle that is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy; and the other of R¹ and R² is absent or isone of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy,wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy;

R³ is absent, or is one of H, C₁-C₂ alkyl, or halogen-substituted C₁-C₂alkyl;

R⁴ is absent, or is one of H, halogen, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl;

R⁶ is H, halogen, or methyl that is optionally is substituted byhalogen;

G is one of —CH═CH—NHC(O)—R⁷, —CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷,—CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷, or —CH₂NHNHC(S)—R⁷,

R⁷ is one of C₁-C₆ alkyl, —O(C₁-C₆ alkyl), —S(C₁-C₆ alkyl), or —N(R⁸)₂;

each R⁸ is independently one of hydrogen or —C₁-C₆ alkyl;

R⁹ is C₁-C₁₀ alkyl or C₂-C₁₀ alkenyl, wherein any C₁-C₁₀ alkyl or C₂-C₁₀alkenyl is optionally substituted by at least one of halogen, hydroxy,alkoxy, or NR^(a)R^(b);

one of R¹² and R¹³ is hydrogen or C₁-C₄ straight alkyl, and the other ofR¹² and R¹³ is C₁-C₁₀ straight or branched alkyl, C₂-C₁₂ straight orbranched hydroxyalkyl, C₂-C₁₂ straight or branched alkenyl, C₂-C₁₂straight or branched hydroxyalkenyl, phenyl, C₇-C₁₂ aralkyl, C₇-C₁₂(aryl)hydroxyalkyl, C₆-C₁₂ heteroaralkyl, C₆-C₁₂(heteroaryl)hydroxyalkyl, or R¹² and R¹³ are taken together with theirintervening atom to form a 4-6 membered ring having 0-1 ring heteroatomsselected from nitrogen, oxygen or sulfur, said ring optionallysubstituted by one or two C₁-C₆ alkyl, C₂-C₆ alkenyl or hydroxyalkylgroups, wherein an alkyl, aryl or heteroaryl moiety of R¹² and R¹³optionally is substituted with 1-3 groups independently selected fromhalo, —C₁-C₆ hydroxyalkyl, —C₁-C₄ alkoxy, —C₁-C₄ trifluoroalkoxy, —CN,—C₁-C₄ alkoxycarbonyl, —C₁-C₄ alkylcarbonyl, —S(C₁-C₄ alkyl), and—SO₂(C₁-C₄ alkyl);

each R^(a) is C₁-C₁₀ alkyl that is optionally substituted by at leastone of halogen, hydroxy, or C₁-C₅ alkoxy; and

each R^(b) is H or C₁-C₁₀ alkyl that is optionally substituted by atleast one of halogen, hydroxy, or C₁-C₅ alkoxy.

In a certain embodiment the invention provides a salt of formula Ia.

In a certain embodiment the invention provides a salt of formula Ib.

In a certain embodiment the invention provides a salt of formula Ic.

In a certain embodiment the invention provides a salt of formula Id.

In a certain embodiment, R⁶ is H.

In a certain embodiment, R⁶ is methyl.

In a certain embodiment, R⁶ is methyl and the salt, or a salt thereof,is a mixture of the R and S stereoisomers.

In a certain embodiment, R⁶ is methyl and the salt, or a salt thereof,is predominantly the R stereoisomer, preferably at least 90% of the Risomer.

In a certain embodiment the invention provides a salt selected from

In a certain embodiment the invention provides a composition that issuitable for intravenous administration.

In a certain embodiment the invention provides a composition thatcomprises water as a pharmaceutically acceptable.

In a certain embodiment of the invention, the composition issubstantially free of organic co-solvents.

In a certain embodiment of the invention, the composition issubstantially free of surfactants.

In a certain embodiment, the invention provides a composition comprisingthe salt of formula (I) and water, wherein the composition issubstantially co-solvent free, substantially surfactant free, and has apH of from about 7 to about 9, and wherein the concentration of the saltis at least about 0.25 mg/mL.

In a certain embodiment, R⁷ is not deuterated alkyl.

Salt Synthesis

Free acids of compounds corresponding to the salts of Formulae Ia-Id canbe prepared, by way of example, as described in U.S. Pat. Nos.9,133,155, 9,187,446, 9,315,495 and 9,592,221, and as in the Examples.

Starting from said free acids, the salts of Formulae Ia-Id can beprepared, by way of example, by contacting with an aqueous solution at apH of at least about 9-10, and preferably at least about 11-12, untilsolids are dissolved, followed by reversed-phase solid-phase extractionor reversed-phase chromatography, for example, as shown in the Examples.

Administration of Pharmaceutical Compositions

The salts of Formulae Ia-Id may be formulated as pharmaceuticalcompositions and administered to a mammalian host, such as a humanpatient in a variety of forms adapted to the chosen route ofadministration (i.e., orally or parenterally, by intravenous,intramuscular, topical or subcutaneous routes).

Thus, the present salts may be systemically administered, e.g., orally,in combination with a pharmaceutically acceptable vehicle such as aninert diluent or an assimilable edible carrier. They may be enclosed inhard or soft shell gelatin capsules, may be compressed into tablets, ormay be incorporated directly with the food of the patient's diet. Fororal therapeutic administration, the active salt may be combined withone or more excipients and used in the form of ingestible tablets,buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers,and the like. Such compositions and preparations should contain at least0.1% of active salt. The percentage of the compositions and preparationsmay, of course, be varied and may conveniently be between about 2 toabout 60% of the weight of a given unit dosage form. The amount ofactive salt in such therapeutically useful compositions is such that aneffective dosage level will be obtained.

The tablets, troches, pills, capsules, and the like may also contain thefollowing: binders such as gum tragacanth, acacia, corn starch orgelatin; excipients such as dicalcium phosphate; a disintegrating agentsuch as corn starch, potato starch, alginic acid and the like; alubricant such as magnesium stearate; and a sweetening agent such assucrose, fructose, lactose or aspartame or a flavoring agent such aspeppermint, oil of wintergreen, or cherry flavoring may be added. Whenthe unit dosage form is a capsule, it may contain, in addition tomaterials of the above type, a liquid carrier, such as a vegetable oilor a polyethylene glycol. Various other materials may be present ascoatings or to otherwise modify the physical form of the solid unitdosage form. For instance, tablets, pills, or capsules may be coatedwith gelatin, wax, shellac or sugar and the like. A syrup or elixir maycontain the active salt, sucrose or fructose as a sweetening agent,methyl and propylparabens as preservatives, a dye and flavoring such ascherry or orange flavor. Of course, any material used in preparing anyunit dosage form should be pharmaceutically acceptable and substantiallynon-toxic in the amounts employed. In addition, the active salt may beincorporated into sustained-release preparations and devices.

The active salt may also be administered intravenously orintraperitoneally by infusion or injection. Solutions of the active saltor its salts can be prepared in water, optionally mixed with a nontoxicsurfactant. Dispersions can also be prepared in glycerol, liquidpolyethylene glycols, triacetin, and mixtures thereof and in oils. Underordinary conditions of storage and use, these preparations contain apreservative to prevent the growth of microorganisms.

The pharmaceutical dosage forms suitable for injection or infusion caninclude sterile aqueous solutions or dispersions or sterile powderscomprising the active ingredient which are adapted for theextemporaneous preparation of sterile injectable or infusible solutionsor dispersions, optionally encapsulated in liposomes. In all cases, theultimate dosage form should be sterile, fluid and stable under theconditions of manufacture and storage. The liquid carrier or vehicle canbe a solvent or liquid dispersion medium comprising, for example, water,ethanol, a polyol (for example, glycerol, propylene glycol, liquidpolyethylene glycols, and the like), vegetable oils, nontoxic glycerylesters, and suitable mixtures thereof. The proper fluidity can bemaintained, for example, by the formation of liposomes, by themaintenance of the required particle size in the case of dispersions orby the use of surfactants. The prevention of the action ofmicroorganisms can be brought about by various antibacterial andantifungal agents, for example, parabens, chlorobutanol, phenol, sorbicacid, thimerosal, and the like. In many cases, it will be preferable toinclude isotonic agents, for example, sugars, buffers or sodiumchloride. Prolonged absorption of the injectable compositions can bebrought about by the use in the compositions of agents delayingabsorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions are prepared by incorporating the activesalt in the required amount in the appropriate solvent with various ofthe other ingredients enumerated above, as required, followed by filtersterilization. In the case of sterile powders for the preparation ofsterile injectable solutions, the preferred methods of preparation arevacuum drying and the freeze drying techniques, which yield a powder ofthe active ingredient plus any additional desired ingredient present inthe previously sterile-filtered solutions.

For topical administration, the present salts may be applied in pureform, i.e., when they are liquids. However, it will generally bedesirable to administer them to the skin as compositions orformulations, in combination with a dermatologically acceptable carrier,which may be a solid or a liquid.

Useful solid carriers include finely divided solids such as talc, clay,microcrystalline cellulose, silica, alumina and the like. Useful liquidcarriers include water, alcohols or glycols or water-alcohol/glycolblends, in which the present salts can be dissolved or dispersed ateffective levels, optionally with the aid of non-toxic surfactants.Adjuvants such as fragrances and additional antimicrobial agents can beadded to optimize the properties for a given use. The resultant liquidcompositions can be applied from absorbent pads, used to impregnatebandages and other dressings, or sprayed onto the affected area usingpump-type or aerosol sprayers.

Thickeners such as synthetic polymers, fatty acids, fatty acid salts andesters, fatty alcohols, modified celluloses or modified mineralmaterials can also be employed with liquid carriers to form spreadablepastes, gels, ointments, soaps, and the like, for application directlyto the skin of the user.

Examples of useful dermatological compositions which can be used todeliver the salts of formula I to the skin are known to the art; forexample, see Jacquet et al. (U.S. Pat. No. 4,608,392), Geria (U.S. Pat.No. 4,992,478), Smith et al. (U.S. Pat. No. 4,559,157) and Wortzman(U.S. Pat. No. 4,820,508).

Useful dosages of the salts of formula I can be determined by comparingtheir in vitro activity, and in vivo activity in animal models. Methodsfor the extrapolation of effective dosages in mice, and other animals,to humans are known to the art; for example, see U.S. Pat. No.4,938,949.

The amount of the salt required for use in treatment will vary not onlywith the particular salt selected but also with the route ofadministration, the nature of the condition being treated and the ageand condition of the patient and will be ultimately at the discretion ofthe attendant physician or clinician.

The salt is conveniently formulated in unit dosage form; for example,containing 5 to 1000 mg, conveniently 10 to 750 mg, most conveniently,50 to 500 mg of active ingredient per unit dosage form. In oneembodiment, the invention provides a composition comprising a salt ofthe invention formulated in such a unit dosage form.

The desired dose may conveniently be presented in a single dose or asdivided doses administered at appropriate intervals, for example, astwo, three, four or more sub-doses per day. The sub-dose itself may befurther divided, e.g., into a number of discrete loosely spacedadministrations; such as multiple inhalations from an insufflator or byapplication of a plurality of drops into the eye.

The following illustrate representative pharmaceutical dosage forms,containing a salt of formula Ia, Ib, Ic, or Id (‘Salt X’), fortherapeutic or prophylactic use in humans:

a) A formulation comprising from about 0.25 mg/ml to about 10 mg/ml ofSalt X in about 10 mM sodium phosphate at about pH 7.4; and

b) A formulation comprising from about 0.25 mg/ml to about 5 mg/ml ofSalt X and about 5% dextrose in about 10 mM sodium phosphate at about pH7.4; and

c) A formulation comprising from about 0.25 mg/ml to about at least 5mg/ml of Salt X in phosphate-buffered saline at about pH 7.4; and

d) A formulation comprising from about 0.25 mg/ml to about 20 mg/ml ofSalt X in about 0 to about 1% carboxymethylcellulose and about 0 toabout 1% Tween 80 at about pH 8.4.

The invention will now be illustrated by the following non-limitingExamples.

EXAMPLES Example 1: 4-hydroxy-6-(pent-4-en-1-yl)-2H-pyran-2-one

4-hydroxy-6-methyl-2H-pyran-2-one (Sigma-Aldrich; 7.57 g; 60 mmol) wasdissolved in 180 ml tetrahydrofuran-hexamethylphosphoramide(Sigma-Aldrich; 150:30 v/v). The solution was cooled to −78° C.;n-butyllithium (54 mL, 2.5M, 0.135 mmol; Sigma-Aldrich) was addeddrop-wise over 30 min. The reaction mixture was stirred 0.5 h at −78°C., another 15 minutes at 0° C. and then brought down to −78° C.4-Bromobutene (12.2 ml; 120 mmol; Sigma-Aldrich) was added drop-wise,and the reaction mixture was stirred overnight, allowing the temperatureto increase to room temperature. The reaction was quenched with 1 M HClto pH 2 and extracted with 4×100 ml ethyl acetate, and the ethyl acetateextracts were pooled, washed with 100 ml brine, dried over anhydroussodium sulfate, and evaporated to an oil. The product was isolated viasilica chromatography (ethyl acetate/hexanes gradient) on a CombiFlashCompanion. Yield: 10.53 g (97%). ¹H NMR (400 MHz, CDCl₃): δ 5.97 (s,1H), 5.70 (m, 1H), 5.58 (s, 1H), 5.00-4.95 (m, 2H), 2.42 (t, 2H), 2.02(m, 2H), 1.85 (m, 2H). MS (API-ESI): calculated: m/z 180.20 (MH⁺);found: 180.91.

Example 2: 4-hydroxy-6-(pent-4-en-1-yl)-3-propionyl-2H-pyran-2-one

N,N′-Diisopropylcarbodiimide (Sigma-Aldrich; 0.42 ml; 2.71 mmol),4-(dimethylamino)pyridine (Sigma-Aldrich; 30 mg; 0.25 mmol), propionicacid (Sigma-Aldrich; 0.204 mL, 2.73 mmol) and4-hydroxy-6-(pent-4-en-1-yl)-2H-pyran-2-one (Example 1, 0.443 g, 2.46mmol) were dissolved in 7 ml toluene and heated 4 h in a 40 mL screw cappressure vial at 100° C. under argon. Upon cooling to 25° C., 14 mlethyl acetate was added to the reaction mixture to precipitate theby-product DIC urea. The reaction mix was filtered, the solid wastriturated with 100 mL ethyl acetate. The organic solutions were pooledand washed with 25 ml 1M HCl, 25 ml water, and 25 ml brine, and wasdried over anhydrous sodium sulfate. The product was isolated via silicachromatography dichloromethane) Yield: 0.331 g (57%). ¹HNMR (400 MHz,CDCl₃): δ 5.96 (s, 1H), 5.80 (m, 1H), 5.05-4.95 (m, 2H), 3.10 (q, 2H),2.50 (t, 2H), 2.10 (m, 2H), 1.80 (m, 2H), 1.18 (t, 3H).

Example 3: methyl(E)-6-(4-hydroxy-2-oxo-3-propionyl-2H-pyran-6-yl)hex-2-enoate

To 4-hydroxy-6-(pent-4-en-1-yl)-3-propionyl-2H-pyran-2-one (Example 2;1.5 g; 6.3 mmol) and methyl crotonate (Sigma-Aldrich; 4.41 ml, 41.6mmol) in 8 ml anhydrous t-butyl methyl ether, was added Hoveyda-GrubbsCatalyst II (Sigma-Aldrich; 130 mg, 0.21 mmol), and the reaction mixturewas heated 16 h at 50° C. The solvent was evaporated, and the productwas isolated via silica chromatography (ethyl acetate/hexanes gradient)on a CombiFlash Companion. Yield: 1.3 g (70%). ¹H NMR (400 MHz, CDCl₃):δ 6.90 (m, 1H), 5.90 (s, 1H), 5.82 (d, 2H), 3.70 (s, 3H), 3.10 (q, 2H),2.50 (t, 2H), 2.10 (m, 2H), 1.80 (m, 2H), 1.18 (t, 3H).

Example 4: 2-(4-fluorophenoxy)thiazole

4-Fluorophenol (Sigma-Aldrich; 4.8 g, 43 mmol) and potassium carbonate(7.4 g, 54 mmol) were mixed in 20 ml anhydrous dimethylformamide, andthe resulting slurry was stirred vigorously 5 h at 130° C. Afterallowing the reaction mixture to cool to 80° C., 2-bromothiazole(Sigma-Aldrich; 5.8 g, 36 mmol) in 5 ml dimethylformamide was addeddropwise over 5 min, and the reaction mixture was heated 16 h at 130° C.After cooling to 25° C., 50 ml water was added, the reaction mixture wasextracted with 3×50 ml ethyl acetate. The extracts were pooled andwashed with 3×25 ml 6% NaOH, 25 ml water, and 25 ml brine, and weredried over anhydrous sodium sulfate and concentrated to a brown oil. Theproduct was isolated via silica chromatography (ethyl acetate/hexanesgradient) on a CombiFlash Companion. Yield: 6.88 g (99%). ¹H NMR (400MHz, CDCl₃): δ 7.27 (m, 2H), 7.22 (d, 2H), 7.10 (d, 2H)

Example 5: 2-(4-fluorophenoxy)thiazole-5-carbaldehyde

Lithium diisopropylamide (LDA) was freshly prepared according to thefollowing procedure: Diisopropylamine (8.1 mL; 57.83 mmol,Sigma-Aldrich) in 60 ml tetrahydrofuran was cooled to −78° C.;n-butyl-lithium (26.5 ml 2.0 M in cyclohexanes; 53 mmol; Sigma-Aldrich)was added drop-wise over 10 min. Stirring was continued for 5 min at 0°C., followed by re-cooling to −78° C. for 30 min. The formed LDA wascannulated into a solution of 2-(4-fluorophenoxy)thiazole (Example 4;6.88 g; 35.3 mm) in 60 mL anhydrous tetrahydrofuran at −78° C. (dry icebath) over 5 min. The reaction was stirred 30 min, 5.5 ml anhydrousdimethylformamide was added drop-wise over 5 min, and stirring wascontinued 10 min. The dry ice bath was removed, and the reaction mixturewas stirred 10 min. The reaction was quenched with 50 ml saturatedammonium chloride and extracted with 3×50 ml ethyl acetate, and thepooled organic extracts were dried with brine and anhydrous sodiumsulfate and evaporated to a brown solid. The product was isolated viasilica chromatography (ethyl acetate/hexanes gradient) on a CombiFlashCompanion. Yield: 4.7 g (60%).

¹H NMR (400 MHz, CDCl₃): δ 9.95 (s, 1H), 8.17 (s, 1H), 7.27 (d, 2H),7.18 (d, 2H).

Example 6: Methyl(E)-6-(3-((E)-3-(2-(4-fluorophenoxy)thiazol-5-yl)-2-methylacryloyl)-4-hydroxy-2-oxo-2H-pyran-6-yl)hex-2-enoate

Methyl (E)-6-(4-hydroxy-2-oxo-3-propionyl-2H-pyran-6-yl)hex-2-enoate(Example 3; 346 mg; 1.18 mmol) and2-(4-fluorophenoxy)thiazole-5-carbaldehyde (Example 5; 264 mg; 1.18mmol) were mixed in 8 ml isopropanol in a sealed vial, warmed untilsolids went into solution, and allowed to cool to 25° C. Piperidine(116.6 μl, 1.18 mm; Sigma-Aldrich) was added, and the reaction mixturewas heated 16 h at 70° C. with vigorous stirring. The reaction mixturewas evaporated to an oil, re-dissolved in 10 ml dichloromethane, shakenvigorously with 25 ml 1 M HCl in a separatory funnel, and re-extractedwith 2×50 ml dichloromethane. The combined dichloromethane extracts werewashed with 25 ml water and 25 ml brine, dried over anhydrous sodiumsulfate, and evaporated to an oil. The product was isolated via silicachromatography (ethyl acetate/hexanes gradient) on a CombiFlashCompanion. Yield: 227 mg (38%). ¹H NMR (500 MHz, CDCl₃): δ 7.37 (s, 1H),7.29 (d, 2H), 7.13 (d, 2H), 7.03 (s, 1H), 6.90 (m, 1H), 5.97 (s, 1H),5.81 (d, 1H), 3.72 (s, 3H), 2.54 (t, 2H), 2.30 (m, 2H), 2.13 (s, 3H),1.88 (m, 2H). MS (MALDI): calculated: m/z 500.51 (MW); found: 500.11.

Example 7: (E)-6-(3-((E)-3-(2-(4-fluorophenoxy)thiazol-5-yl)-2-methylacryl oyl)-4-hydroxy-2-oxo-2H-pyran-6-yl)hex-2-enoic acid

To methyl(E)-6-(3-((E)-3-(2-(4-fluorophenoxy)thiazol-5-yl)-2-methylacryloyl)-4-hydroxy-2-oxo-2H-pyran-6-yl)hex-2-enoate(Example 6; 150 mg; 0.300 mmol) in 13.2 ml t-butanol and 2.7 ml water,was added 1.65 ml 1M LiOH. The mixture was microwaved (BiotageInitiator; Biotage) 1 h at 60° C. Upon cooling to 25° C., the reactionmixture was evaporated to dryness, re-dissolved in 30 ml ethyl acetateand 20 ml 0.5 M HCl, adjusted to pH˜2, and extracted with 3×20 ml ethylacetate. The combined extracts were washed with brine, dried overanhydrous sodium sulfate, and evaporated to an oil. The product wasisolated via silica chromatography (ethyl acetate/hexanes gradient) on aCombiFlash Companion. Yield: 0.133 g (90%). ¹H NMR (500 MHz, CDCl₃): δ7.37 (s, 1H), 7.29 (d, 2H), 7.13 (d, 2H), 7.03 (s, 1H), 6.90 (m, 1H),5.97 (s, 1H), 5.81 (d, 1H), 2.54 (t, 2H), 2.30 (m, 2H), 2.13 (s, 3H),1.88 (m, 2H). MS (MALDI): calculated: m/z 486.48 (MH⁺); found: 486.11.

Example 8

The title compound was obtained by conversion of(E)-6-(3-((E)-3-(2-(4-fluorophenoxy)thiazol-5-yl)-2-methylacryloyl)-4-hydroxy-2-oxo-2H-pyran-6-yl)hex-2-enoicacid (Example 7) into the acyl azide, followed by Curtius rearrangementunder thermal conditions to yield the isocyanate, followed by additionof deuterated methanol. To(E)-6-(3-((E)-3-(2-(4-fluorophenoxy)thiazol-5-yl)-2-methylacryloyl)-4-hydroxy-2-oxo-2H-pyran-6-yl)hex-2-enoicacid (Example 7; 1.31 g, 2.63 mmol) and diisopropylamine (Sigma-Aldrich;2.25 ml; 13 mmol) in anhydrous acetone (200 ml) under argon at 0° C.,was added ethyl chloroformate (Sigma-Aldrich); 0.95 ml; 9.9 mmol), andthe reaction mixture was stirred 1.5 h at 0° C. Sodium azide (1.7 g; 13mmol) in 50 ml water was added, the reaction was stirred 45 min at 0°C., and the reaction was quenched by addition of 50 ml ice-water. The pHof the mixture was adjusted to ˜2 by addition of 1 N HCl. Organics wereextracted with 3×50 ml ethyl acetate, and the combined extracts werewashed with 50 ml brine, dried over anhydrous sodium sulfate, evaporatedto an oil, and trace water was removed by azeotropic evaporation ofadded anhydrous toluene azeotrope (3×30 ml). The crude azide was furtherdried 20 min under high vacuum, then re-dissolved in anhydrous toluene(140 ml) and heated 2 h at 110° C. The reaction mixture was allowed tocool to 80° C., and 70 ml anhydrous deuterated methanol (methanol-d4,99.8 atom % D; Sigma-Aldrich) was added, and heating was continued for12 h at 80° C. The reaction mixture was allowed to cool to roomtemperature, and evaporated to dryness. The product was isolated viasilica chromatography (ethyl acetate/hexanes gradient) on a CombiFlashCompanion. Deuterated methanol was recovered for future use bydistillation. Yield: 0.984 g (70%). ¹H NMR (500 MHz, CDCl₃): δ 7.36 (s,1H), 7.27 (d, 2H), 7.15 (d, 2H), 7.11 (s, 1H), 6.51-6.43 (broad t, 1H),6.25-6.17 (broad d, 1H), 5.97 (s, 1H), 4.99-4.88 (m, 1H), 2.51 (t, 2H),2.13 (s, 3H), 2.05 (m, 2H), 1.75 (m, 2H). MS (MALDI): calculated: m/z518.54 (MH⁺); found: 518.17.

Example 9

The compound of Example 8 (241 mg, 0.466 mmol) was suspended in 160 ml50 mM sodium carbonate, and the suspension was stirred 3 h at 25° C.until all solids dissolved. Aliquots (32 ml each) of the resultingsolution were applied to 10 g HF Mega BE-C18 reversed-phase cartridges(Agilent; prepared for use by one cycle of filling to rim withacetonitrile and draining and two cycles of filling to rim with waterand draining), washed with 2×50 ml degassed water, and eluted with 5×20ml 50% methanol, monitoring elution by monitoring yellow color. Pooledfactions containing the title compound (first two 50% methanolfractions). were evaporated to yield a yellow crystalline solid. Yield:210 mg (84%). ¹H NMR (500 MHz, CD₃OD): δ 7.44 (s, 1H), 7.42 (s, 1H),7.37 (d, 2H), 7.23 (d, 2H), 6.43 (d, 1H), 5.71 (s, 1H), 5.10 (m, 1H),2.42 (t, 2H), 2.13 (m, 2H), 2.06 (s, 3H), 1.70 (m, 2H). MS (MALDI):calculated: m/z 540.54 (M+Na⁺); found: 540.17.

Example 10

Example 10 was prepared analogously to Example 9, but using potassiumcarbonate in place of sodium carbonate.

Example 11

Example 11 was prepared as described for Examples 4-8, but using3-chloro-4-fluorophenol (Sigma-Aldrich) in place of 4-fluorophenol inthe first reaction step. Yield (last reaction step): 47 mg (45%). ¹H NMR(500 MHz, CDCl₃): δ 7.42 (br s, 1H), 7.34 (s, 1H), 7.15 (m, 2H), 7.02(s, 1H), 6.51-6.43 (broad t, 1H), 6.25-6.17 (broad d, 1H), 5.97 (s, 1H),4.99-4.88 (m, 1H), 2.51 (t, 2H), 2.13 (s, 3H), 2.05 (m, 2H), 1.75 (m,2H). MS (MALDI): calculated: m/z 552.98 (MH⁺); found: 551.99, 553.95.

Example 12

The compound of Example 11 (26 mg, 47 μmol) was suspended in 15 ml 50 mMsodium carbonate and stirred for 16 h at 25° C. The resulting solutionwas applied to a 10 g HF Mega BE-C18 reversed-phase cartridge (Agilent;prepared for use by one cycle of filling to rim with acetonitrile anddraining and two cycles of filling to rim with water and draining),washed with 2×50 ml degassed water, and eluted with 10 ml 50% methanol,10 ml 75% methanol, and 10 ml 80% methanol, monitoring elution bymonitoring yellow color. Pooled factions containing the title compound(first two fractions) were evaporated to yield a yellow crystallinesolid. Yield: 18 mg (67%).

Example 13

Example 13 was prepared as described for Examples 4-8, but using4-phenylphenol (Sigma-Aldrich) in place of 4-fluorophenol in the firstreaction step. Yield (last reaction step): 82 mg (70%. ¹H NMR (500 MHz,CDCl3): δ 7.66-7.25 (m, 9H), 7.34 (s, 1H), 7.05 (s, 1H), 6.51-6.43(broad t, 1H), 6.25-6.17 (broad d, 1H), 5.97 (s, 1H), 4.99-4.88 (m, 1H),2.51 (t, 2H), 2.13 (s, 3H), 2.05 (m, 2H), 1.75 (m, 2H). MS (MALDI):calculated: m/z 575.65 (M+H⁺); found: 576.01, 597.99 (M+Na⁺).

Example 14

The compound of Example 13 (15 mg, 20 μmol) was suspended in 12 ml 50 mMsodium carbonate and stirred for 16 h at 25° C. The resulting solutionwas applied to a 10 g HF Mega BE-C18 reversed-phase cartridge (Agilent;prepared for use by one cycle of filling to rim with acetonitrile anddraining and two cycles of filling to rim with water and draining),washed with 2×50 ml degassed water, and eluted with 10 ml 50% methanol,10 ml 75% methanol, and 10 ml 80% methanol, monitoring elution bymonitoring yellow color. Pooled factions containing the title compound(first two fractions) were evaporated to yield a yellow crystallinesolid. Yield: 12 mg (58%).

Example 15: Assay of Solubility: Dilution from Organic Solvent intoAqueous Buffer

Serial dilutions of test articles were prepared in dimethyl sulfoxide at100× the final concentration. Test article solutions and blanks werediluted 100× into phosphate-buffered saline (PBS; 0.01 M sodiumphosphate, pH 7.4, 137 mM NaCl, and 3 mM KCl) in a 96-well plate andmixed. After 2 h at 37° C., the presence of precipitate was detected byturbidity (absorbance at 540 nm). An absorbance value of greater than“mean+3×SD of the blank” (after subtracting background) was consideredan indication of turbidity. The solubility limit was reported as thehighest tested concentration with no evidence of turbidity. Data forrepresentative compounds are provided in Table 1.

Example 16: Assay of Solubility; Dissolution in Aqueous Buffer inAbsence of Organic Solvent

Starting with 0.5-5 mg test compound in a glass vial at roomtemperature, successive cycles of addition of vehicle, vortexing 15 s,and inspection were performed until all test compound dissolved.Vehicles were: 0.01 M sodium phosphate (pH 7.4); 5% dextrose in 0.01 Msodium phosphate (pH 7.4); and 0.5% carboxymethylcellulose (CMC)/0.5%Tween-80 (pH 8.4). Data for representative compounds are provided inTable 2.

Example 17: Assay of Inhibition of Bacterial RNA Polymerase Example17.1: Assay of Inhibition of Escherichia coli RNA Polymerase

Fluorescence-detected RNA polymerase assays with E. coli RNA polymerasewere performed by a modification of the procedure of Kuhlman et al.,2004 [Kuhlman, P., Duff, H. & Galant, A. (2004) A fluorescence-basedassay for multisubunit DNA-dependent RNA polymerases. Anal. Biochem.324, 183-190]. Reaction mixtures contained (20 μl): 0-100 nM test salt,75 nM E. coli RNA polymerase σ⁷⁰ holoenzyme, 20 nM 384 bp DNA fragmentcontaining the bacteriophage T4 N25 promoter, 100 μM ATP, 100 μM GTP,100 μM UTP, 100 μM CTP, 50 mM Tris-HCl, pH 8.0, 100 mM KCl, 10 mM MgCl₂,1 mM DTT, 10 μg/ml bovine serum albumin, and 5.5% glycerol. Reactioncomponents other than DNA and NTPs were pre-incubated for 10 min at 37°C. Reactions were carried out by addition of DNA and incubation for 5min at 37° C., followed by addition of NTPs and incubation for 60 min at37° C. DNA was removed by addition of 1 μl 5 mM CaCl₂ and 2 U DNaseI(Ambion, Inc.), followed by incubation for 90 min at 37° C. RNA wasquantified by addition of 100 μl RiboGreen RNA Quantitation Reagent(Invitrogen, Inc.; 1:500 dilution in Tris-HCl, pH 8.0, 1 mM EDTA),followed by incubation for 10 min at 25° C., followed by measurement offluorescence intensity [excitation wavelength=485 nm and emissionwavelength=535 nm; QuantaMaster QM1 spectrofluorometer (PTI, Inc.)].IC50 is defined as the concentration of inhibitor resulting in 50%inhibition of RNA polymerase activity.

Example 17.2: Assay of Inhibition of Mycobacterium tuberculosis RNAPolymerase

Fluorescence-detected RNA polymerase assays with M. tuberculosis RNApolymerase were performed as in Example 17.1, using reaction mixturescontaining (20 μl): 0-100 nM test salt, 75 nM M. tuberculosis RNApolymerase core enzyme, 300 nM M. tuberculosis σ ^(A), 20 nM 384 bp DNAfragment containing the bacteriophage T4 N25 promoter, 100 μM ATP, 100μM GTP, 100 UTP, 100 μM CTP, 40 mM Tris-HCl, pH 8.0, 80 mM NaCl, 5 mMMgCl₂, 2.5 mM DTT, and 12.7% glycerol. IC50 is defined as theconcentration of inhibitor resulting in 50% inhibition of RNA polymeraseactivity.

Example 17.3: Assay of Inhibition of Staphylococcus aureus RNAPolymerase

Fluorescence-detected RNA polymerase assays with S. aureus RNApolymerase were performed as in Example 17.1, using reaction mixturescontaining (20 μl): 0-100 nM test salt, 75 nM S. aureus RNA polymerasecore enzyme, 300 nM S. aureus σ ^(A), 20 nM 384 bp DNA fragmentcontaining the bacteriophage T4 N25 promoter, 100 μM ATP, 100 μM GTP,100 μM UTP, 100 CTP, 40 mM Tris-HCl, pH 8.0, 80 mM NaCl, 5 mM MgCl₂, 2.5mM DTT, and 12.7% glycerol. IC50 is defined as the concentration ofinhibitor resulting in 50% inhibition of RNA polymerase activity.

Data for representative compounds from the assays of Example 17 areprovided in Table 3.

Example 18: Assay of Inhibition of Bacterial Growth in Culture Example18.1: Assay of Inhibition of Growth of Staphylococcus aureus andEscherichia coli

Minimum inhibitory concentrations (MICs) for Staphylococcus aureus ATCC12600 and Escherichia coli D21f2tolC were quantified using spiralgradient endpoint assays, essentially as described [Wallace, A. andCorkill, J. (1989) Application of the spiral plating method to studyantimicrobial action. J. Microbiol. Meths. 10, 303-310; Paton, J., Holt,A., and Bywater, M. (1990) Measurement of MICs of antibacterial agentsby spiral gradient endpoint compared with conventional dilution methods.Int. J. Exp. Clin. Chemother. 3, 31-38; Schalkowsky S. (1994) Measuresof susceptibility from a spiral gradient of drug concentrations. Adv.Exp. Med. Biol. 349, 107-120]. Assays employed exponential-gradientplates containing 150 mm×4 mm Mueller-Hinton II cation-adjusted agar and0.4-100 μg/ml of test salt. Plates were prepared using an Autoplate 4000spiral plater (Spiral Biotech, Inc.). Saturated overnight cultures wereswabbed radially onto plates, and plates were incubated for 16 h at 37°C. For each culture, the streak length was measured using a clearplastic template (Spiral Biotech, Inc.), the test-salt concentration atthe streak endpoint was calculated using the program SGE (SpiralBiotech, Inc.), and the MIC was defined as the calculated test-saltconcentration at the streak endpoint.

Example 18.2: Assay of Inhibition of Growth of Mycobacteriumtuberculosis

MICs for Mycobacterium tuberculosis H37Rv were quantified usingmicroplate Alamar Blue assays as described [Collins, L. & Franzblau, S.(1997) Microplate Alamar Blue assay versus BACTEC 460 system forhigh-throughput screening of salts against Mycobacterium tuberculosisand Mycobacterium avium. Antimicrob. Agents Chemother. 41, 1004-1009].

Data for representative compounds from the assays of Example 18 areprovided in Table 4.

Example 19. Assay of Antibacterial Efficacy in Mouse Model ofStaphylococcus aureus Systemic Infection (“Peritonitis Model”)

Female Swiss Webster mice (0.18-0.22 kg) were experimentally infected byintraperitoneal administration of 1×10⁷ colony forming units ofmethicillin-resistant Staphylococcus aureus (MRSA) strain BAA-1707(USA-400, MW2) in 5% hog gastric mucin. Test compounds in vehicle (5%dextrose in 10 mM sodium phosphate, pH 7.4), positive control in vehicle(linezolid at 12.5 mg/kg), and negative control (vehicle only), wereadministered by intravenous injection into a tail vein (200 μl) 0 hpost-infection to provide single intravenous doses of 1.56, 3.125, 6.25,12.5, 25, and 50 mg/kg or by oral gavage (400 μl) 1 h pre-infection toprovide single oral doses of 3.125, 6.25, 12.5, 25, 50, and 100 mg/kg.Survival was monitored for 72 h post-infection. Identities of test saltsand controls were blinded from personnel performing injections andmonitoring survival. The effective dose 50 (ED50) was defined as thetest-compound dose resulting in 50% survival at 72 h (calculated usingthe probit method).

Data for representative compounds from the assay of Example 19 areprovided in Tables 5 and 6.

Example 20. Assay of Antibacterial Efficacy in Mouse Model ofStaphylococcus aureus Lung Infection (“Neutropenic Pneumonia Model”)

Female Swiss Webster mice (0.18-0.20 kg) were rendered immunosuppressedby oral gavage for 4 days with cyclophosphamide and were infected byintranasal administration of 1×10⁸ colony forming units ofmethicillin-resistant Staphylococcus aureus (MRSA) strain BAA-1707(USA-400, MW2). Test compounds in vehicle (5% dextrose in 10 mM sodiumphosphate, pH 8.25), positive control in vehicle (vancomycin at 100mg/kg), and negative control (vehicle only), were administered byintravenous injection into a tail vein (200 μl) 1 h post-infection toprovide single intravenous doses of 25, 50, and 100 mg/kg or by oralgavage (200 μl) 1 h post-infection to provide oral doses of 100, 200,and 400 mg/kg. Mice were euthanized and lungs were harvested andhomogenized 24 h post-infection; and viable bacteria were quantified.The effective dose (ED(2 log)) was defined as the minimum test-compounddose resulting in log reduction in bacterial burden.

Data for representative compounds from the assay of Example 20 areprovided in Tables 7 and 8.

Example 21. Assay of Antibacterial Efficacy in Mouse Model ofStaphylococcus aureus Dermal Infection (“Dermal-Infection Model”)

Female BALB/c mice (0.18-0.20 kg) were experimentally infected bytopical administration under isfluurane anesthesia of 1×10⁷ colonyforming units of methicillin-resistant Staphylococcus aureus (MRSA)strain BAA-1707 (USA-400, MW2) to a 20 mm×20 mm dorsal surface preparedby depiliation (24 h pre-infection; isoflurane anesthesia) and removalof epidermis by tape stripping (immediately pre-infection; isofluraneanesthesia; seven applications and removals of 3M Nexcare surgicaltape). Test compounds in vehicle (5% dextrose in 10 mM sodium phosphate,pH 8.25), positive control in vehicle (linezolid at 12.5 mg/kg), andnegative control (vehicle only), were administered by intravenousinjection into a tail vein (200 μl) 0 h post-infection to provide singleintravenous doses of 12.5, 25, 50, and 100 mg/kg. Mice were euthanizedand a 10 mm×10 mm skin segment was harvested and homogenized 24 hpost-infection; and viable bacteria were quantified. Identities of testsalts and controls were blinded from personnel performing injections andquantifying bacteria. The effective dose (ED(2 log)) was defined as theminimum test-compound dose resulting in log reduction in bacterialburden.

Data for representative compounds from the assay of Example 21 areprovided in Table 9.

Example 22. Assay of Antibacterial Efficacy in Mouse Model ofMycobacterium tuberculosis Aerosol Acute Infection (“Mtb Acute InfectionModel”)

Female Balb/c mice (6-8 weeks old) were infected by aerosoladministration of 50-100 colony forming units of Mycobacteriumtuberculosis Erdman. Test compounds in vehicle (5% dextrose in 10 mMsodium phosphate, pH 8.25), positive control in vehicle (rifampi at 10and 20 mg/kg), and negative control (vehicle only), were administered byoral gavage (200 μl) starting 7 days post-infection and continuing for12 days to provide 12 daily oral doses of 100 and 200 mg/kg. Mice wereeuthanized and lungs and spleens were harvested and homogenized 21 dayspost-infection; and viable bacteria were quantified. The effective dose(ED(2 log)) was defined as the minimum test-compound dose resulting inlog reduction in bacterial burden.

Data for representative compounds from the assay of Example 22 areprovided in Table 10.

Screening data for representative salts of this invention (Example 9,Example 10, Example 12, and Example 14) and for the corresponding freeacids (Example 8 and Example 11, and Example 13) are presented in Tables1-10:

TABLE 1 Solubility: dilution from organic solvent into aqueous buffer.Compound solubility (mg/ml) Example 9 (salt) ≥5 Example 8 (free acid)0.1

TABLE 2 Solubility; dissolution in aqueous buffer in absence of organicsolvent solubility solubility 5% dextrose in solubility aqueous buffer,aqueous buffer, 0.5% CMC/0.5% pH 7.4 pH 7.4 Tween, pH 8.4 compound(mg/ml) (mg/ml) (mg/ml) Example 9 10 5 20 (salt) Example 8 <0.1 <0.1<0.1 (free acid)

TABLE 3 Inhibition of bacterial RNA polymerase RNAP-inhibitoryRNAP-inhibitory RNAP-inhibitory activity activity activity M.tuberculosis S. aureus E. coli RNAP RNAP RNAP compound IC50 (μM) IC50(μM) IC50 (μM) Example 9 0.03 0.03 0.003 (salt) Example 10 0.006 (salt)Example 12 0.03 0.003 0.003 (salt) Example 14 >6 0.03 0.05 (salt)Example 8 0.02 0.06 0.004 (free acid) Example 11 0.03 0.001 0.003 (freeacid) Example 13 >6 0.01 0.02 (free acid)

TABLE 4 Inhibition of bacterial growth in vitro in vitro in vitroantibacterial antibacterial antibacterial activity activity activity M.tuberculosis S. aureus E. coli H37Rv ATCC12600 D21f2tolC compound MIC(μg/ml) MIC (μg/ml) MIC (μg/ml) Example 9 0.4 0.4 0.04 (salt) Example 100.2 0.03 (salt) Example 12 0.8 0.2 0.03 (salt) Example 14 >50 >8 0.03(salt) Example 8 0.8 0.3 0.06 (free acid) Example 11 0.8 0.2 0.02 (freeacid) Example 13 >50 >8 0.03 (free acid)

TABLE 5 Antibacterial efficacy in mice: methicillin-resistantStaphylococcus aureus (MRSA) peritonitis, intravenous administration oftest compound in 5% dextrose, 10 mM sodium phosphate, pH 7.4 (singledose). in vivo antibacterial activity: mouse MRSA peritonitis CompoundED50 (mg/kg) Example 9 (salt) 10

TABLE 6 Antibacterial efficacy in mice: methicillin-resistantStaphylococcus aureus (MRSA) peritonitis, oral administration of testcompound in in 5% dextrose, 10 mM sodium phosphate, pH 7.4 (singledose). in vivo antibacterial activity: mouse MRSA peritonitis CompoundED50 (mg/kg) Example 9 (salt) 10

TABLE 7 Antibacterial efficacy in mice: methicillin-resistantStaphylococcus aureus (MRSA) lung infection, intravenous administrationof test compound in 5% dextrose, 10 mM sodium phosphate, pH 8.25 (singledose) in vivo antibacterial activity: mouse MRSA pneumonia Compound ED(2log) (mg/kg) Example 9 (salt) 25

TABLE 8 Antibacterial efficacy in mice: methicillin-resistantStaphylococcus aureus (MRSA) lung infection, oral administration of testcompound in in 5% dextrose, 10 mM sodium phosphate, pH 7.4. in vivoantibacterial activity: mouse MRSA pneumonia Compound ED(2 log) (mg/kg)Example 9 (salt) 100

TABLE 9 Antibacterial efficacy in mice: methicillin-resistantStaphylococcus aureus (MRSA) dermal infection, intravenousadministration of test compound in in 5% dextrose, 10 mM sodiumphosphate, pH 8.25 (single dose). in vivo antibacterial activity: mouseMRSA dermal infection Compound ED(2 log) (mg/kg) Example 9 (salt) 10

TABLE 10 Antibacterial efficacy in mice: methicillin-resistantMycobacterium tuberculosis aerosol acute infection, oral administrationof test compound in in 5% dextrose, 10 mM sodium phosphate, pH 8.25 (12daily doses). in vivo antibacterial activity: mouse Mycobacteriumtuberculosis aerosol acute infection Compound ED(2 log) (mg/kg) Example9 (salt) 200

The data in Table 1 show that a salt of this invention (EXAMPLE 9) is atleast approximately 50 times more soluble than the corresponding freeacid (Example 8) upon dilution from organic solvent into aqueous buffer.

The data in Table 2 show that a salt of this invention (EXAMPLE 9) is atleast approximately 100 times more soluble than the corresponding freeacid (Example 8) upon dissolution in aqueous buffer at pH 7.4 in theabsence of organic solvent or surfactant.

The data in Table 2 further show that a salt of this invention (EXAMPLE9) is at least approximately 50 times more soluble than thecorresponding free acid (Example 8) upon dissolution in 5% dextrose inaqueous buffer at pH 7.4 in the absence of organic solvent.

The data in Table 2 further show that a salt of this invention (EXAMPLE9) is at least approximately 200 times more soluble than thecorresponding free acid (Example 8) upon dissolution in 0.5% CMC/0.5%Tween (pH 8.4) in the absence of organic solvent.

The data in Tables 1-2 show that a salt of this invention (EXAMPLE 9),unlike the corresponding free acid (Example 8), can be formulated atconcentrations up to at least approximately 10 mg/ml in aqueous vehiclesnear neutral pH in the absence of organic solvent and at concentrationsup to at least approximately 10 mg/ml in aqueous vehicles near neutralpH in the absence of both organic solvent and surfactant.

The data in Table 3 show that certain compounds of this inventionpotently inhibit bacterial RNA polymerases.

The data in Table 4 show that certain compounds of this inventionpotently inhibit the Gram-positive bacteria Mycobacterium tuberculosisand Staphylococcus aureus, and the Gram-negative bacterium Escherichiacoli.

The data in Tables 5-10 indicate that certain compounds of thisinvention potently treat infections prevent death from bacterialinfection in a mammal. Table 5 presents data for survival fromexperiments with mice with systemic infections of methicillin-resistantStaphylococcus aureus (MRSA) and compounds administered intravenously.Table 6 presents data for survival from experiments with mice withsystemic infections of methicillin-resistant Staphylococcus aureus(MRSA) and compounds administered intravenously or orally.

The data in Tables 6-10 indicate that certain compounds of thisinvention potently treat infections and reduce bacterial burdens in amammal. Tables 7 and 8 presents data for reductions in plasma bacterialburdens from experiments with mice with lung infections ofmethicillin-resistant Staphylococcus aureus (MRSA) and test compoundsadministered intravenously or orally. Table 9 presents data forreductions in bacterial burdens from experiments with mice with dermalinfections of methicillin-resistant Staphylococcus aureus (MRSA) andcompounds administered intravenously. Table 10 presents data forreductions in bacterial burdens from experiments with mice with aerolsolacute infections of Mycobacterium tuberculosis and test compoundsadministered orally.

The data in Tables 5-10 further indicate that certain compounds of thisinvention can be administered to mammals intravenously at doses up to atleast 100 mg/kg or orally at doses up to at least 400 mg/kg whenformulated in an aqueous vehicle near neutral pH in the absence of bothorganic solvent and surfactant.

1. A salt of formula Ia, Ib, Ic, or Id:

wherein: W is sulfur, oxygen, or nitrogen; X, Y, and Z are individuallycarbon, sulfur, oxygen, or nitrogen, wherein at least two of X, Y, and Zare carbon; one of R¹ and R² is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀alkoxy, aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy, is optionally substituted by atleast one of halogen, hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, orfuranyl, and wherein any aryloxy or heteroaryloxy is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₅ alkyl, C₁-C₅alkoxy, aryl, or heteroaryl, wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy,aryl, and heteroaryl is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅ alkoxy; or one of R¹ and R² is a5-6-membered saturated, partially unsaturated, or aromatic heterocyclethat is optionally substituted by at least one of halogen, hydroxy,C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the other of R¹ andR² is absent or is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, orC₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀alkoxy is optionally substituted by at least one of halogen, hydroxy, orC₁-C₅ alkoxy; R³ is absent, or is one of H, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl; R⁴ is absent, or is one of H, halogen,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl; V′, W′, X′, Y′, and Z′are individually carbon or nitrogen; wherein at least three of V′, W′,X′, Y′, and Z′ are carbon; one of R^(1′) and R^(2′) is C₁-C₁₀ alkyl,C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy, aryloxy, heteroaryloxy, or NR^(a)R^(b),wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy, isoptionally substituted by at least one of halogen, hydroxy, C₁-C₅alkoxy, tetrahydrofuranyl, or furanyl, and wherein any aryloxy orheteroaryloxy is optionally substituted by at least one of halogen,hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, or heteroaryl, wherein anyC₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroaryl is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅alkoxy; or one of R^(1′) and R^(2′) is a 5-6-membered saturated,partially unsaturated, or aromatic heterocycle that is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy; and the other of R^(1′) and R^(2′) is absentor is one of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy,wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy;R^(3′), R^(4′), and R^(5′) are each independently absent, H, halogen,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl; W″ is sulfur, oxygen,or nitrogen; U″, V″, X″, Y″, and Z″ are individually carbon, sulfur,oxygen, or nitrogen, wherein at least three of U″, V″, X″, Y″, and Z″are carbon; one of R^(1″) and R^(2″) is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl,C₁-C₁₀ alkoxy, aryloxy, heteroaryloxy, or NR^(a)R^(b), wherein anyC₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy, is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₅ alkoxy,tetrahydrofuranyl, or furanyl, and wherein any aryloxy or heteroaryloxyis optionally substituted by at least one of halogen, hydroxy, C₁-C₅alkyl, C₁-C₅ alkoxy, aryl, or heteroaryl, wherein any C₁-C₅ alkyl, C₁-C₅alkoxy, aryl, and heteroaryl is optionally substituted by at least oneof halogen, hydroxy, C₁-C₅ alkyl, or C₁-C₅ alkoxy; or one of R^(1″) andR^(2″) is a 5-6-membered saturated, partially unsaturated, or aromaticheterocycle that is optionally substituted by at least one of halogen,hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy; and the otherof R^(1″) and R^(2″) is absent or is one of H, halogen, C₁-C₁₀ alkyl,C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy, wherein any C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy is optionally substituted by at least one ofhalogen, hydroxy, or C₁-C₅ alkoxy; R^(3″) is absent or is one of H,C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl; R^(4″), R^(5″), andR^(6″) are each independently absent, H, halogen, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl; R⁶ is H, halogen, or methyl that isoptionally is substituted by halogen; G is one of —CH═CH—NHC(O)—R⁷,—CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷, —CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷,or —CH₂NHNHC(S)—R⁷, R⁷ is one of C₁-C₆ alkyl, —O(C₁-C₆ alkyl), —S(C₁-C₆alkyl), or —N(R⁸)₂; each R⁸ is independently one of hydrogen or —C₁-C₆alkyl; R⁹ is C₁-C₁₀ alkyl or C₂-C₁₀ alkenyl, wherein any C₁-C₁₀ alkyl orC₂-C₁₀ alkenyl is optionally substituted by at least one of halogen,hydroxy, alkoxy, or NR^(a)R^(b); one of R¹² and R¹³ is hydrogen or C₁-C₄straight alkyl, and the other of R¹² and R¹³ is C₁-C₁₀ straight orbranched alkyl, C₂-C₁₂ straight or branched hydroxyalkyl, C₂-C₁₂straight or branched alkenyl, C₂-C₁₂ straight or branchedhydroxyalkenyl, phenyl, C₇-C₁₂ aralkyl, C₇-C₁₂ (aryl)hydroxyalkyl,C₆-C₁₂ heteroaralkyl, C₆-C₁₂ (heteroaryl)hydroxyalkyl, or R¹² and R¹³are taken together with their intervening atom to form a 4-6 memberedring having 0-1 ring heteroatoms selected from nitrogen, oxygen orsulfur, said ring optionally substituted by one or two C₁-C₆ alkyl,C₂-C₆ alkenyl or hydroxyalkyl groups, wherein an alkyl, aryl orheteroaryl moiety of R¹² and R¹³ optionally is substituted with 1-3groups independently selected from halo, —C₁-C₆ hydroxyalkyl, —C₁-C₄alkoxy, —C₁-C₄ trifluoroalkoxy, —CN, —C₁-C₄ alkoxycarbonyl, —C₁-C₄alkylcarbonyl, —S(C₁-C₄ alkyl), and —SO₂(C₁-C₄ alkyl); each R^(a) isC₁-C₁₀ alkyl that is optionally substituted by at least one of halogen,hydroxy, or C₁-C₅ alkoxy; each R^(b) is H or C₁-C₁₀ alkyl that isoptionally substituted by at least one of halogen, hydroxy, or C₁-C₅alkoxy; and M⁺ is a pharmaceutically acceptable cation.
 2. The salt ofclaim 1, wherein the salt of formula Ia is a salt of Ia′ and the salt offormula Id is a salt of formula Id′

wherein: W is sulfur, oxygen, or nitrogen; X, Y, and Z are individuallycarbon, or nitrogen, wherein at least two of X, Y, and Z are carbon; oneof R¹ and R² is C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, C₁-C₁₀ alkoxy, aryloxy,heteroaryloxy, or NR^(a)R^(b), wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl,or C₁-C₁₀ alkoxy, is optionally substituted by at least one of halogen,hydroxy, C₁-C₅ alkoxy, tetrahydrofuranyl, or furanyl, and wherein anyaryloxy or heteroaryloxy is optionally substituted by at least one ofhalogen, hydroxy, C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, or heteroaryl,wherein any C₁-C₅ alkyl, C₁-C₅ alkoxy, aryl, and heteroaryl isoptionally substituted by at least one of halogen, hydroxy, C₁-C₅ alkyl,or C₁-C₅ alkoxy; or one of R¹ and R² is a 5-6-membered saturated,partially unsaturated, or aromatic heterocycle that is optionallysubstituted by at least one of halogen, hydroxy, C₁-C₁₀ alkyl, C₂-C₁₀alkenyl, or C₁-C₁₀ alkoxy; and the other of R¹ and R² is absent or isone of H, halogen, C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy,wherein any C₁-C₁₀ alkyl, C₂-C₁₀ alkenyl, or C₁-C₁₀ alkoxy is optionallysubstituted by at least one of halogen, hydroxy, or C₁-C₅ alkoxy; R³ isabsent, or is one of H, C₁-C₂ alkyl, or halogen-substituted C₁-C₂ alkyl;R⁴ is absent, or is one of H, halogen, C₁-C₂ alkyl, orhalogen-substituted C₁-C₂ alkyl; R⁶ is H, halogen, or methyl that isoptionally is substituted by halogen; G is one of —CH═CH—NHC(O)—R⁷,—CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷, —CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷,or —CH₂NHNHC(S)—R⁷, R⁷ is one of C₁-C₆ alkyl, —O(C₁-C₆ alkyl), —S(C₁-C₆alkyl), or —N(R⁸)₂; each R⁸ is independently one of hydrogen or —C₁-C₆alkyl; R⁹ is C₁-C₁₀ alkyl or C₂-C₁₀ alkenyl, wherein any C₁-C₁₀ alkyl orC₂-C₁₀ alkenyl is optionally substituted by at least one of halogen,hydroxy, alkoxy, or NR^(a)R^(b); one of R¹² and R¹³ is hydrogen or C₁-C₄straight alkyl, and the other of R¹² and R¹³ is C₁-C₁₀ straight orbranched alkyl, C₂-C₁₂ straight or branched hydroxyalkyl, C₂-C₁₂straight or branched alkenyl, C₂-C₁₂ straight or branchedhydroxyalkenyl, phenyl, C₇-C₁₂ aralkyl, C₇-C₁₂ (aryl)hydroxyalkyl,C₆-C₁₂ heteroaralkyl, C₆-C₁₂ (heteroaryl)hydroxyalkyl, or R¹² and R¹³are taken together with their intervening atom to form a 4-6 memberedring having 0-1 ring heteroatoms selected from nitrogen, oxygen orsulfur, said ring optionally substituted by one or two C₁-C₆ alkyl,C₂-C₆ alkenyl or hydroxyalkyl groups, wherein an alkyl, aryl orheteroaryl moiety of R¹² and R¹³ optionally is substituted with 1-3groups independently selected from halo, —C₁-C₆ hydroxyalkyl, —C₁-C₄alkoxy, —C₁-C₄ trifluoroalkoxy, —CN, —C₁-C₄ alkoxycarbonyl, —C₁-C₄alkylcarbonyl, —S(C₁-C₄ alkyl), and —SO₂(C₁-C₄ alkyl); each R^(a) isC₁-C₁₀ alkyl that is optionally substituted by at least one of halogen,hydroxy, or C₁-C₅ alkoxy; and each R^(b) is H or C₁-C₁₀ alkyl that isoptionally substituted by at least one of halogen, hydroxy, or C₁-C₅alkoxy.
 3. The salt of claim 1, which is a salt of formula Ia.
 4. Thesalt of claim 1, which is a salt of formula Ib.
 5. The salt of claim 1,which is a salt of formula Ic.
 6. The salt of claim 1, which is a saltof formula Id.
 7. The salt of claim 1, wherein R⁶ is H.
 8. The salt ofclaim 1, wherein R⁶ is methyl.
 9. The salt of claim 8, or a saltthereof, wherein R⁶ is methyl and where the salt is a mixture of the Rand S stereoisomers.
 10. The salt of claim 8, or a salt thereof, whereinR⁶ is methyl and wherein the salt, or a salt thereof, is predominantlythe R stereoisomer, preferably at least 90% of the R isomer. 11.(canceled)
 12. A composition comprising the salt of claim 1 and apharmaceutically acceptable carrier.
 13. The composition of claim 12,which is suitable for intravenous administration.
 14. The composition ofclaim 12 or 13, wherein the pharmaceutically acceptable carrier iswater.
 15. The composition of claim 14, that is substantially free oforganic co-solvents.
 16. The composition of claim 15, that issubstantially free of surfactants.
 17. A composition comprising the saltof claim 1 and water, wherein the composition is substantiallyco-solvent free, substantially surfactant free, and has a pH of fromabout 7 to about 9, and wherein the concentration of the salt is atleast about 0.25 mg/mL. 18-23. (canceled)
 24. A method of inhibiting abacterial RNA polymerase, comprising contacting a bacterial RNApolymerase with a salt of claim
 1. 25. A method of treating a bacterialinfection in a mammal, comprising administering to the mammal atherapeutically effective amount of a salt of claim
 1. 26. The method ofclaim 25 wherein an aqueous composition comprising the salt isadministered intravenously to the mammal.
 27. A method for preparing asalt as described in claim 1, comprising contacting a corresponding freeacid with an aqueous solution at a pH of at least about 9 (e.g. at leastabout 10, 11, or 12), until solids are dissolved, and isolating the saltby reversed-phase solid-phase extraction or reversed-phasechromatography.
 28. The salt of claim 1 wherein G is one of—CH═CH—NHC(S)—R⁷, —CH₂CH₂NHC(O)—R⁷, —CH₂CH₂NHC(S)—R⁷, —CH₂NHNHC(O)—R⁷,or —CH₂NHNHC(S)—R⁷.
 29. The salt of claim 1 wherein G is—CH═CH—NHC(O)—R⁷ and R⁷ is not deuterated alkyl.